Silane diimidic tetracarboxylic perylene dyes

ABSTRACT

Silane diimidic tetracarboxylic perylene dyes, the composite pigments obtainable therefrom by means of grafting onto an inorganic substrate, and the processes for preparing same. 
     The dyes have the general formula: ##STR1## in which R is the residue of a silane group of formula: ##STR2## in which n is 3, 4 or 5; q is 0 or 1, p and m are such integers than when q is 0, p is 3 and m is 0, 1, 2 or 3, and when q is 1, p is 2 and m is 0, 1 or 2; R 2  is an alkyl C 1  -C 4  or a phenyl; R 3  is an alkoxyl C 1  -C 2  ; R 1  may be the same as R or represent an alkyl C 1  -C 6 , a cycloalkyl, a phenyl optionally substituted by one or more alkyl or alkoxyl groups C 1  -C 6  or a halogen. 
     The dyes and the composite pigments obtained from said dyes are utilized in paints, air and stove enamels, in the pigmentation of plastic materials, and in printing inks.

DESCRIPTION

This invention relates to diimidic tetracarboxylic perylene dyes,briefly referred to as "perylene" dyes, containing chemically combinedtherewith at least one silane group, and to the corresponding silanecomposite pigments, preparable by association thereof with an organicsolid substrate.

Whenever used in the following description, "silane composite pigment"means a pigmentary material consisting or consisting essentially of anassociation of perylene dyes containing at least one silane group, withan inorganic solid substrate or support.

The above association of the perylene dye containing at least one silanegroup or, briefly, silane perylene dye, with the solid substrate impartsto the silane perylene dye the pigmentary characteristics which aretypical of the inorganic pigments.

Such association is obtained through the formation of chemical bonds(grafting) between the silane moiety of the dye and the inorganicsubstrate.

An object of the present invention is that of providing silane perylenedyes useful for preparing pigments endowed with excellentcharacteristics; in particular, highly hiding or fully transparent, andexhibiting excellent stabilities to solvents.

Further objects reside in the preparation of the above dyes and pigmentsby simple and economic methods.

These and still other objects, which will be apparent from the detaileddescription given hereinafter, are achieved by the silane perylene dyesand by the silane composite pigments derivable therefrom, by graftingonto the surface of an inorganic substrate, and by the processes forpreparing them.

Thus, an object of the present invention is the perylene dyes containingat least one silane group of formula: ##STR3## in which R is the residueof a silane group of formula: ##STR4## in which n is 3, 4 or 5; q is 0or 1; p and m are such integers that when q is 0, p is 3 and m is 0, 1,2 or 3, and when q is 1, p is 2 and m is 0, 1 or 2; R₂ is an alkylhaving up to 4 carbon atoms or a phenyl; R₃ is an alkoxyl having up to 2carbon atoms; R₁ may be like R or represent an alkyl having up to 6carbon atoms, a cycloalkyl, a phenyl optionally substituted by one ormore halogens or alkyl groups or alkoxyl groups containing up to 6carbon atoms.

They are prepared by means of a process consisting or consistingessentially in reacting 3,4,9,10-perylenetetracarboxylic dianhydride ofthe formula: ##STR5## with a compound of formula: ##STR6## in which R₂,R₃, n, q, p and m are as defined above, and optionally with a compoundof the formula:

    R.sub.4 --NH.sub.2                                         (V)

wherein R₄ is an alkyl having up to 6 carbon atoms, a cycloalkyl or aphenyl optionally substituted by one or more alkyls, alkoxyls orhalogens, in a reaction medium consisting or consisting essentially ofwater and/or organic solvents, at a temperature ranging from 130° to240° C., during 6 to 24 hours.

When one wants to obtain a dye containing two silane groups, one uses asilane compound (IV):dianhydride (III) molar ratio of at least 2.

When one wants to obtain a dye containing only one silane group, oneuses at least one mole of silane compound (IV) and at least one mole ofamine (V) for each mole of dianhydride (III).

The reaction may be optionally carried out in the presence of a Zn salt,such as, e.g., zinc chloride and zinc acetate, in amounts varying from 1to 50% by weight in respect to the dianhydride employed.

It is possible to operate in a water suspension, in mixtures of waterand organic solvents miscible with water, or in organic solvents.

As water-miscible organic solvents there may be utilized, for example,dioxane, dimethylformamide, pyridine, and as water-immiscible solvents,for example, quinoline, trichlorobenzene, alpha-chloronaphthalene andnitrobenzene.

When using water or mixtures of water and organic solvents, the reactionis preferably carried out in a closed reactor, under an autogenouspressure, utilizing compound (V) in the form of hydrochloride. Theproduct obtained from the reaction is usually hot-washed with alkaline,acid and neutral water, then with methanol, and finally dried at ambienttemperature.

The perylene tetracarboxylic 3,4,9,10-dianhydride (III) is a known andcommercially available product.

As silane compounds of formula (IV), those derived fromamino-alkoxy-silanes, such as, for example,γ-aminopropyltriethoxysilane, δ-amino-butyl-triethoxysilane,δ-amino-butylphenyl-diethoxysilane, γ-aminopropyl-methyl-diethoxysilane,have proved particularly suitable. Said amino-alkoxy-silanes are knownand commercially available compounds.

However, they may be prepared according to conventional techniques, forexample, by reacting the corresponding chloroalkoxy-silanes withaliphatic amines.

As amines of formula (V) there may be employed, for instance, the linearaliphatic amines, such as methylamine, ethylamine, propylamine,butylamine, pentylamine, hexylamine, the corresponding branched chainamines, such as sec.butylamine, ter.butylamine and isopropylamine, thecycloalkyl amines, such as cyclohexylamine and morpholine, the aromaticamines, such as aniline, the ortho-, meta- or para-toluidines,anisidines or chloroanilines, the 2,4- or 3,5-xylidines, dianisidines ordichloroanilines, 2-methyl-4-chloroaniline,2,5-dimethoxy-4-chloroaniline, 2,4-dimethoxy-5-chloroaniline.

The silane perylene dyes of formula (I) possess in themselves goodpigmentary characteristics, such as good stability to solvents, and inapplications in stove alkyd enamels or in the pigmentation of plasticmaterials; they provide products endowed with a high tinting strength,good general stabilities and pure shades.

The silane perylene dyes of formula (I), as they contain in theirmolecules silanol groups and/or alkoxyl groups hydrolyzable to silanolgroups --Si(OH)₃, are capable of both self-condensing by reaction amongthe above-said silanol groups, and of chemically reacting with thesurface hydroxyl groups of proper inorganic substrates which condensewith those, with formation of a stable chemical bond (grafting) betweenthe dye and the substrate, giving rise to a composite product havingexcellent pigmentary characteristics.

The above dyes are therefore most preferably used for preparingcomposite pigments--this being a further object of the presentinvention--consisting of the silane perylene dyes of formula (I) graftedon an inorganic support.

Particularly suitable for being utilized in the preparation of compositepigments are the silane dyes of formula: ##STR7## wherein n, m, p and R₃have the meanings given above, as well as silane dyes of formula:##STR8## wherein R₁, different from R, n, m, p and R₃, have the meaningsgiven above.

As inorganic substrates or supports which are particularly suited forensuring the pigmentary nature of the silane perylene dyes of formula(I), the following are advantageously employed: TiO₂, in its gel,semicrystalline, rutile or anatase forms, also of the commercial type,in which there may be present surface coatings consisting of mixtures ofone or more oxides selected from SiO₂, Al₂ O₃, TiO₂ ; furthermore, theremay be used mechanical mixtures of TiO₂ with SiO₂ and/or Al₂ O₃, as wellas SiO₂ and/or Al₂ O₃, said supports being finely particled. The mixedsubstrates of TiO₂, SiO₂ and/or Al₂ O₃ obtained by precipitation of SiO₂and/or Al₂ O₃, also as alumino-silicates, onto crystalline TiO₂particles, according to conventional methods, are preferably due totheir superior characteristics.

In relation to the uses, hiding degree or tinting strength to beobtained, the above-mentioned substrates may also be utilized inadmixture with one another.

The specific surface of said substrates can vary over a wide range, from5 to 500 m² /g, and preferably from 10 to 200 m² /g.

The composite pigments containing from 10 to 50% by weight of the silaneperylene dye of formula (I) in grafted form are particularly preferred,owing to their superior characteristics.

The process for preparing the composite pigments composed of the silaneperylene dyes (I) grafted on the above inorganic substrates consists orconsists essentially in treating the selected substrate with the silanedye (I), in a reaction medium consisting or consisting essentially ofwater and/or inert organic solvents at a temperature ranging from 20° C.to the reflux temperature of the reaction medium, and then in separatingthe resulting product by filtration, in washing and then drying it.

Such treatment can be advantageously carried out by grinding the silanedyes with the substrate in said reaction medium. Such treatment may lastfrom 2 to 12 hours, depending on the reaction temperature employed.

Particularly advantageous results are obtained if the composite pigmentis subjected to a dry heat treatment in an oven for 4-8 hours at 80° to140° C.

Suitable inert organic solvents are, for example, quinoline,dimethylformamide, N-methylpyrrolidone, dichloro- andtrichloro-benzenes, dimethylsulphoxide and n-heptane.

The process of this invention has proved particularly suitable forobtaining intensely colored pigments having a high tinting strength,even in the presence of inorganic substrates having a low specificsurface, such as, e.g., highly hiding TiO₂.

The composite pigments of the present invention may have a compositevarying over a wide range, in relation to the nature, particle size, andspecific surface of the substrate particles, and in relation to thetinting strength desired for the pigment.

The granulometric analysis of the composite pigment reveals that theorganic moiety is prevailingly distributed on the surface of theinorganic substrate particles.

The X-ray diffractometric analysis indicates that the composite pigmentparticles exhibit the crystallinity which is typical of the substrate,while the grafted silane perylene coating proves to be of an amorphousnature.

The grafted silane perylene pigments of the present invention do notexhibit--thanks to their composite nature brought about by the chemicalbonds between the silane organic component and the inorganiccomponent--the defects which are typical of simple physical mixtures,wherefore they do not give rise to the phenomena of demixing,differentiated sedimentation, crystallization of the components, andthey do not change their crystalline form when coming into contact witharomatic solvents, even under hot conditions.

Furthermore, the solvent-based pigmentary compositions, such as thoseused for printing inks, do not cause sedimentation phenomena, not evenafter long-lasting storage.

The above pigments, either in the highly hiding form or in thetransparent form, exhibit excellent pigmentary characteristics, areinsoluble in the common organic and aqueous solvents, exhibit very goodstabilities to migration in polyvinyl chloride (PVC), to overpainting instove alkyd enamels, and to acid or alkaline treatments. Such pigmentsare endowed with a good photostability and a good tinting strength, andare stable to heat when obtained both in the transparent form and atincreasing degrees of hiding.

Thus, they are most preferably utilized in painting products for air andstove enamels, in the pigmentation of plastic materials, such as PVC,polystyrene, polyethyleneterephthalate, etc., and in printing inks,according to conventional application techniques.

The mechanical and/or thermal treatments used in said conventionaltechniques do not substantially modify the pigmentary characteristics ofthe composite pigments of this invention.

Said composite pigments exhibit the essential advantage of beingcomposed of an inorganic portion or substrate, which is not veryexpensive and is capable of imparting excellent pigmentarycharacteristics, among which, in particular, the desired hiding ortransparency degree and the excellent stability to solvents, onto whichsubstrate a silane perylene dye, characterized by high photostability,tinting strength and shade purity, is grafted.

The present invention will now be described still more in detail in thefollowing examples, which are given for illustrative purposes and not byway of limitation.

The parts and percentages, unless otherwise specified, are by weight.

EXAMPLE 1

An autoclave, charged with 7.84 g of 3,4,9,10-perylenetetracarboxylicdianhydride, 10.4 g of γ-aminopropyl-triethoxysilane and 40 g of water,was heated to 200° C. during 8 hours under autogenous pressure.

The reaction mass was discharged and filtered at 60° to 80° C., washedat 50° to 50° C. with neutral water, alkaline water due to KOH at 1%,then again with water to neutrality, and finally with methanol. Anintensely red-colored powder was obtained by drying which, on analysis,gave the following results:

    C=57%; H=42%; N=4.3%; Si=9%.

The powder, subjected to I.R. spectroscopic analysis, exhibited thebands typical of silanol groups .tbd.Si(OH) around 3500 cm⁻¹ and thoseof the imidic groups ##STR9## at 1650 cm⁻¹ and 1695 cm⁻¹, while thebands typical of the anhydride group were absent.

The above analytical and spectroscopic data essentially corresponds to adye of formula: ##STR10##

Said dye can also be partially present in oligomeric form by formationof siloxane bonds --Si--O--Si-- among the silanol functionalities--Si(OH)₃ present in the molecule.

EXAMPLE 2

A closed reactor, charged with 7.84 g of3,4,9,10-perylenetetracarboxylic dianhydride, 5.23 g ofγ-aminopropyltriethoxysilane and 50 g of water, was heated to 200° C.during 8 hours.

After cooling to room temperature, 1.42 g of propylamine were addedthereto, and the reactor was heated again to 180° C. during 8 hours.

After cooling to a temperature of 60° to 80° C., the product wasdischarged, filtered and washed as in Example 1.

An intensely dark red-colored powder was obtained which by drying, onanalysis, gave the following results:

    C=65%; H=4.5%; N=5%; Si=6%.

From the analytical and I.R. spectroscopic data, which revealed theabsence of bands of the anhydride group, the presence of .tbd.SiOH andimide bands, said powder was shown to substantially correspond to a dyeof formula: ##STR11##

Said dye can also be partially present in the oligomeric form.

EXAMPLE 3

A closed reactor, under a nitrogen atmosphere, charged with 3.92 g of3,4,9,10-perylenetetracarboxylic dianhydride, 4.98 g of↓-aminopropyltriethoxysilane and 50 g of water, was heated to 180° C.for 10 hours.

After cooling to room temperature, 5.11 g of aniline and 0.5 g of zincchloride were added, and the reactor was heated again to 220° C. for 12hours.

After cooling, the product was filtered, hot-washed with water acidifiedwith HCl, then alkaline with KOH (1%) and at last neutral, then with amixture of water and dimethyl formamide at 50%, then with methanol, andfinally dried.

An intensely red-colored power was obtained which, on analysis, gave thefollowing results:

    C=67%; H=4%; N=4.5%; Si=4.9%.

From the analytical and I.R. spectroscopic data, said powder was shownto essentially correspond to a dye of formula: ##STR12##

The dye may be partially present in the oligomeric form.

EXAMPLE 4

An autoclave charged, under a nitrogen atmosphere, with 1.806 parts of3,5-xylidine, as an aqueous solution of the corresponding hydrochloride,3.92 parts of 3,4,9,10-perylenetetracarboxylic dianhydride, 50 parts ofwater and 0.5 parts of ZnCl₂, was heated to 220° C. during 12 hours.

The resulting product was filtered, hot-washed with water, methanol anddried, then it was reacted again in the autoclave under autogenouspressure, with 3.297 parts of γ-aminopropyl-triethoxysilane, in 50 partsof water, while heating at 220° C. for 12 hours.

The resulting product, separated and dried in like manner as in Example1, consisted of an intense red powder which, on analysis, gave thefollowing results:

    C=67.5%; H=4.5%; N=4%; Si=5.5%.

From the analytical data and from the I.R. spectroscopic analysis, theproduct was shown to essentially correspond to a dye of formula:##STR13##

The dye can be partially present in the oligomeric form.

Such dye was also obtained according to a variant of the aboveprocedure, i.e., by first carrying out the reaction between thedianhydride and the γ-aminopropyltriethoxysilane and, successively, thereaction with 3,5-xylidine in the form of the chloride.

EXAMPLE 5

By reacting 3.92 parts of 3,4,9,10-perylenetetracarboxylic dianhydridewith 4.98 parts of γ-aminopropyltriethoxysilane, in a first step, andsuccessively with 3.69 parts of para-anisidine in the form ofhydrochloride, in water, according to procedures analogous with thosedescribed in Example 4, a red product was obtained which, on analysis,gave the following results:

    C=65%; H=4%; N=4%; Si=5%.

From analytical data and from the I.R. spectroscopic analysis, thisproduct corresponded to: ##STR14##

The dye may be partially present in the oligomeric form.

EXAMPLE 6

A silane perylene composite pigment was prepared by using a mixedinorganic substrate of TiO₂, SiO₂ and Al₂ O₃, prepared as follows: 100parts of TiO₂ were dispersed, under mechanical stirring, in 1 liter ofwater, and the dispersion was then heated to 60° C.

After a 15-minute stirring, 210 ml of a sodium silicate solution (titer:365.47 parts/l of SiO₂) were added, and successively, in 3 hours, 200 mlof an aluminum sulphate solution (titer: 60 parts/l of Al₂ O₃) wereadditioned. The addition was stopped when the pH of the slurry reached avalue of 6. It was left under stirring for 1 hour, whereafter theproduct was filtered, washed with water in order to remove the solublesalts, and finally dried at a temperature of 70° C.

The dry product was crushed and then ground in an automatic mortar. Awhite power (A) was obtained, the composition thereof being as follows:

    TiO.sub.2 =43.4%; SiO.sub.2 =35.1%; Al.sub.2 O.sub.3 =7.15%; H.sub.2 O=14.35%.

and having a specific surface, determined on the Sorptometer, of 120 m²/g, an actual specific gravity of 2.74 g/ml, an apparent specificgravity of 0.69 g/cc, a % porositity of 7.45, and a total porosity of1.06 ml/g.

2 parts of the substrate so obtained and 1 part of the dye obtained inExample 1 were ground during 12 hours under wet condition in xylene,then heated to 140° C. during 4 hours and filtered at room temperature.

The resulting product was then placed into an oven at 110° C. and leftthere overnight, whereafter it was hot-washed withxylene-dimethylformamide at 50%, methanol, and then dried.

An intense red powder was obtained which, on elemental analysis,consisted of 68% of inorganic components.

Said powder proved to be particularly stable to treatments, even underhot conditions, with organic solvents or with water.

In applications in stove alkyd enamels and in polyvinylchloride, the redpowder provided highly hiding red products endowed with an excellenttinting strength, stability to overpainting, to migration and to light,when present both in mass and when diluted with TiO₂.

The composite pigment in powder form revealed, on X-ray diffractometricanalysis, radiation CuK α 1.5418, to consist of particles having thecrystallinity typical of TiO₂ rutile, while SiO₂, Al₂ O₃ and the silaneperylene coating proved to be amorphous.

EXAMPLE 7

One part of the dye obtained according to Example 1 was introduced intoa reactor along with 70 parts of water, 1 part of TiO₂ and 2.1 ml of asodium silicate solution (SiO₂ titer: 365.47 parts/liter).

The suspension was heated to 60° C. and, under stirring, it wasadditioned in 3 hours with 2 ml of an aluminum sulphate solution (Al₂ O₃titer: 60 parts/liter), maintained at 60° C. during 1 hour and thencooled down to room temperature.

After filtration, the resulting cake was washed with water until neutralpH, dried in an oven at 110° C. overnight, then repeatedly washed withhot water and finally dried.

An intensely red-colored powder was obtained which, on elementalanalysis, proved to consist of 67.5% of inorganic components.

The product exhibited application characteristics of stability, hidingpower, tinting strength, as well as diffractometric characteristicssimilar to those of the product obtained according to Example 6.

EXAMPLE 8

1 part of the dye obtained in Example 1 was introduced into a reactorwith 70 parts of water, 4.2 ml of a sodium silicate solution (SiO₂titer: 365.47 parts/l).

The suspension was heated to 60° C. and, under stirring, it wasadditioned in 3 hours with 4 ml of an aluminum sulphate solution (Al₂ O₃titer: 60 parts/l), then it was maintained at 60° C. during 1 hour,whereupon it was cooled to ambient temperature.

After filtration, the resulting cake was washed with water to neutralpH, dried in an oven at 110° C. overnight, then repeatedly washed withhot water and, at last dried.

A red powder was obtained which, on analysis, was found to consist of68.5% of inorganic components.

The composite pigment was revealed, on X-ray analysis, to consist ofamorphous particles.

This powder, employed in stove enamel and in polyvinyl chloride,provided red, fully transparent, products endowed with excellentstability and photostability.

EXAMPLES 9-19

By operating according to the procedures of Examples 6 to 8 andutilizing the silane perylene dyes of Examples 1 to 5, in combinationwith the inorganic substrates indicated in Table 1 below, 11 redpigments of different shades were prepared with different hiding powerand transparency degrees and with stability characteristics similar tothose of the products obtained in Examples 6 to 8.

                  TABLE 1                                                         ______________________________________                                        Example  Dye of the Example                                                                            Inorganic Substrate                                  ______________________________________                                         9       1               TiO.sub.2 - SiO.sub.2                                10       1               TiO.sub.2 - Al.sub.2 O.sub.3                         11       1               SiO.sub.2                                            12       1               Al.sub.2 O.sub.3                                     13       2               TiO.sub.2 - SiO.sub.2 - Al.sub.2 O.sub.3             14       2               SiO.sub.2                                            15       3               SiO.sub.2                                            16       3               TiO.sub.2 - SiO.sub.2                                17       3               TiO.sub.2 - SiO.sub.2 - Al.sub.2 O.sub.3             18       4               TiO.sub.2 - SiO.sub.2 - Al.sub.2 O.sub.3             19       5               TiO.sub.2 - SiO.sub.2 - Al.sub.2 O.sub.3             ______________________________________                                    

EXAMPLE 20 (Application in PVC)

In a rotary-arm mixer there were mixed, at 70° C.:

1.0 part of the pigment obtained according to Example 6 and previouslyground;

100 parts of polyvinyl chloride in powder form (PVC);

1.5 parts of calcium stearate acting as a complexing and stabilizingagent;

3.0 parts of epoxidized soybean oil;

0.5 parts of lubricant (a mixture of glycerides from C₁₆ to C₃₆); and

2.0 parts of TiO₂.

The mixture thus obtained was then treated at 180° C. in a three-rollrefiner until complete dispersion of the pigment in order to obtain ahighly hiding red sheet endowed with a good color intensity, a goodphotostability, a good tinting strength, a good stability to heat, andan excellent stability to migration.

EXAMPLE 21 (Application in Enamel)

5.0 parts of the pigment obtained according to Example 6 were mixed bygrinding with 95.0 parts of a fluid carrier having the followingcomposition:

22% of alkyd resin;

19% of melamine resin; and

59% of xylene.

Homogenization was carried out in a ball mill by grinding the mixture inthe presence of porcelain spheres of 10 mm diameter, during 24 hours.

The enamel so obtained was applied onto the surface to be painted,allowed to dry overnight, and then it was placed in an oven and leftthere for 30 minutes at 120° to 125° C.

A red paint having excellent hiding power, stability to sunlight and tooverpainting, and a good tinting strength was obtained.

In order to obtain a paint exhibiting a lighter shade and a higherhiding power, 1 part of the enamel, obtained as described above, wasfurther diluted with 9 parts of a white synthetic stove enamel (10%TiO₂) having the following composition:

30% of alkyd resin;

27% of melamine resin;

33% of xylene; and

10% of TiO₂.

Homogenization was carried out in a ball mill by grinding the mixture inthe presence of porcelain spheres of 10 mm diameter, during 24 hours.

The cut enamel so obtained was applied onto the surface to be paintedand allowed to dry overnight, whereafter it was placed in an oven andkept there at 120° to 125° C. during 30 minutes.

A light red paint was obtained, which exhibited excellent generalstabilities and a high hiding power.

EXAMPLE 22 (Application in Polystyrene)

0.04 g of the pigment, prepared according to Example 6 and previouslyground, were added to 100 g of polystyrene (EDISTIR NA, a Montedisonregistered trademark) previously dried, and then calendered at 160° C.for 5 minutes.

The dyed material was cut and then crushed in a geared apparatus.

To evaluate the shade, tinting strength and thermostability, moldingswere carried out in a CARVER press at 200° C. and at 260° C.

A molded article exhibiting a hiding red shade and characterized by agood thermostability and a good photostability was thus obtained.

What is claimed is:
 1. A heterocyclic compound containing at least onesilane group and having the formula: ##STR15## in which R is a silanegroup of formula: ##STR16## wherein n is 3, 4 or 5; q is 0 or 1; p and mare integers, such that when q is 0, p is 3 and m is 0, 1, 2 or 3, andwhen q is 1, p is 2 and m is 0, 1 or 2; R₂ is an alkyl having up to 4carbon atoms or a phenyl; R₃ is an alkoxyl having up to 2 carbon atoms;R₁ may be the same as R or may be an alkyl having up to 6 carbon atoms,a cycloalkyl, a phenyl optionally substituted by one or more halogens oralkyl or alkoxyl groups containing up to 6 carbon atoms.
 2. Aheterocyclic compound according to claim 1, having the formula:##STR17##
 3. A heterocyclic compound according to claim 1, having theformula: ##STR18##
 4. A heterocyclic compound according to claim 1,having the formula: ##STR19##
 5. A heterocyclic compound according toclaim 1, having the formula: ##STR20##
 6. A heterocyclic compoundaccording to claim 1, having the formula: ##STR21##